Light-absorbing composition and optical filter

1. A light-absorbing composition comprising:

a light absorber including a phosphonic acid represented by the following formula (a) and copper ion;

a hydrolysis-polycondensation product of an alkoxysilane monomer for dispersing the light absorber; and

a silicone resin,

wherein the light absorbing composition does not contain a phosphoric acid ester having a polyoxyalkyl group,

wherein a molar ratio of a content of the alkoxysilane monomer to a content of the copper ion is 2.0 or more

wherein the alkoxysilane includes at least two selected from the group consisting of a tetrafunctional alkoxysilane, a trifunctional alkoxysilane, and a bifunctional alkoxysilane, and a molar ratio of total amount of the trifunctional alkoxysilane and the bifunctional alkoxysilane to the copper ion is 1.839 to 17.652; and

wherein a light-absorbing film formed from the light-absorbing composition having a wavelength band of 100 nm or more, the wavelength band being a range of wavelengths with a normalized transmittance of 70% or more in a normalized transmittance spectrum, and

the normalized transmittance spectrum is obtained by normalizing a transmittance spectrum such that the spectral transmittance at a wavelength of 700 nm is 20%, the transmittance spectrum is a spectrum for light with wavelengths from 300 nm to 1200 nm incident perpendicularly to the light-absorbing film:

wherein R 11 is an alkyl group, an aryl group, a nitroaryl group, a hydroxyaryl group, or a halogenated aryl group in which at least one hydrogen atom in an aryl group is substituted by a halogen atom.

2. The light-absorbing composition according to claim 1 , wherein the alkoxysilane monomer comprises the alkyl group-containing the alkoxysilane monomer represented by the following formula (b):

(R 2 ) n —Si—(OR 3 ) 4-n   (b)

wherein R 2 is an alkyl group having 1 to 4 carbon atoms, R 3 is an alkyl group having 1 to 8 carbon atoms, and n is an integer of 1 to 3.

3. The light-absorbing composition according to claim 2 , wherein the phosphonic acid comprises a phosphonic acid represented by the formula (a), wherein R 11 is an aryl group, a nitroaryl group, a hydroxyaryl group, or a halogenated aryl group in which at least one hydrogen atom in an aryl group is substituted by a halogen atom,

the alkoxysilane monomer comprises the alkyl group-containing the alkoxysilane monomer represented by the formula (b) where n=1 or 2 and a tetrafunctional alkoxysilane monomer represented by the formula (c), and

a molar ratio of a content of the alkyl group-containing alkoxysilane monomer represented by the formula (b) where n=1 or 2 to a content of the copper ion is 2.5 or more,

Si—(OR 4 ) 4   (c)

wherein R 4 is an alkyl group having 1 to 8 carbon atoms.

4. An optical filter comprising a light absorbing layer,

the light absorbing layer including:

a light absorber including a phosphonic acid represented by the following formula (a);

a copper ion;

a hydrolysis-polycondensation product of an alkoxysilane monomer, and

a silicone resin,

wherein the light absorbing layer does not contain a phosphoric acid ester having a polyoxyalkyl group,

wherein a molar ratio of a content of the alkoxysilane monomer to a content of the copper ion is 2.0 or more,

wherein the alkoxysilane includes at least two selected from the group consisting of a tetrafunctional alkoxysilane, a trifunctional alkoxysilane, and a bifunctional alkoxysilane, and a molar ratio of total amount of the trifunctional alkoxysilane and the bifunctional alkoxysilane to the copper ion is 1.839 to 17.652;

the optical filter has a first wavelength band of 100 nm or more, the first wavelength band being a range of wavelengths with a normalized transmittance of 70% or more in a normalized transmittance spectrum, and

the normalized transmittance spectrum is obtained by normalizing a transmittance spectrum such that the spectral transmittance at a wavelength of 700 nm is 20%, the transmittance spectrum is a spectrum for light with wavelengths from 300 nm to 1200 nm incident perpendicularly to the optical filter:

wherein R 11 is an alkyl group, an aryl group, a nitroaryl group, a hydroxyaryl group, or a halogenated aryl group in which at least one hydrogen atom in an aryl group is substituted by a halogen atom.

5. The optical filter according to claim 4 , the optical filter further having a second wavelength band of 40 nm or more, the second wavelength band being a range of wavelengths with a transmittance of 80% or more in the normalized transmittance spectrum.

6. The optical filter according to claim 4 , the optical filter further having a third wavelength band of 120 nm or more, the third wavelength band being a range of wavelengths with a transmittance of 20% or less in a range of wavelength of 700 nm to 1200 nm in the normalized transmittance spectrum.

7. The optical filter according to claim 4 , the optical filter, in the normalized transmittance spectrum, further having:

a fourth wavelength band in which the transmittance decreases with an increase in wavelength;

a fifth wavelength band in which the transmittance increases with an increase in wavelength, the fifth wavelength band including a wavelength shorter than a minimum wavelength in the fourth wavelength band;

a first cut-off wavelength with the transmittance of 50% in the fourth wavelength band; and

a second cut-off wavelength with the transmittance of 50% in the fifth wavelength band,

wherein a difference obtained by subtracting the second cut-off wavelength from the first cut-off wavelength is 200 nm to 290 nm.

8. The optical filter according to claim 4 , the optical filter, in the normalized transmittance spectrum, further having:

a first wavelength with a maximum transmittance in a range of wavelength of 500 nm to 550 nm; and

a second wavelength with a minimum transmittance in a range of wavelength of 700 nm to 1200 nm,

wherein a difference obtained by subtracting the first wavelength from the second wavelength is from 240 nm to 360 nm.

9. The optical filter according to claim 4 , wherein, in the normalized transmittance spectrum, a difference obtained by subtracting a minimum transmittance in a range of wavelength of 700 nm to 1200 nm from a maximum transmittance is more than 68%.

10. The optical filter according to claim 4 , the silicone resin having an aryl group.